One thing that I wondered about when looking at the longest recorded professional games that occurred in real play was at what point they reached a position tha

One thing that I wondered about when looking at the longest recorded professional games that occurred in real play was at what point they reached a position that is actually solved in a tablebase. In particular, chess endgames involving only 7 pieces were explicitly solved by computer search in 2012. (But I also wonder if bringing those solutions to bear in a real game would involve ignoring the 50-move rule, since tablebase solution for these positions may often require more than 50 moves to complete.) On tablebase-informed endgame theory, some of the professionals in these ultra-long games should probably have resigned long before the actual end of the games, except that they can also assume that their opponents don't know the full solutions.